Many car parks have a limited capacity, may need to know in advance a forecast of customers for a seamless operation of shuttle services or the planning of valet services
Some car parks require prepayment to guarantee the reservation or access to the best rates. There is a 100% refund policy for prepaid bookings online if cancelled with at least a 1h notice prior to departure.
In case of No Show without prior notice, the carpark may apply its policy for customers not shown, which is detailed in the booking. This may imply no refund for prepaid bookings.